Lab talk

Jun 8, 2010

Peptide templates pattern nanoparticles

Genetically engineered peptides, which are designed to bind to two different inorganic materials, enable the deposition and patterning of nanoparticles on a solid substrate and can be used to generate multi-component patterns by means of micro-contact printing.

Inspired by biomineralization processes, researchers at the Ben Gurion University of the Negev, Israel, have demonstrated the use of peptides with affinities to two different inorganic materials as single-layer linkers for deposition and patterning of nanoparticles. The feasibility of the developed patterning processes for use in microelectronics and nanoelectronics applications was demonstrated by the choice of two technologically important nanoparticle systems: carbon nanotubes (CNTs) and gold colloids, which were deposited on silica surfaces.

Two peptides were designed. One end of both peptides incorporated an amino-acid sequence that binds to silica, and the other end incorporated a sequence that binds either to the CNTs or gold. Nanoparticle assembly was achieved either by first attaching the peptide to the substrate and depositing the target nanoparticle on top, or by using the peptide to form a stable dispersion of the nanoparticles, which was then used as an ink in the deposition process.

The organic nature of the peptides allows them to be used as templates for micro-contact printing of inorganic patterns on surfaces. Using this technique, patterns of both types of nanoparticles on silica have been achieved. Furthermore, a multi-nanoparticle pattern of both the CNTs and gold colloids on the substrate was obtained, as shown in the AFM images above.

The striped pattern of the gold colloids is clearly observed in the topography image as diagonal lines (left panel), whereas the vertical lines in the phase image are comprised of the CNTs (centre panel). This is further demonstrated by the high-resolution phase image (right panel), in which four distinct areas are observed containing both CNTs and gold colloids (I), only CNTs (II), gold colloids (III) and bare silica (IV).

The team's work demonstrates that the modularity and versatility of peptides can be explored as a powerful tool for the fabrication of devices based on a variety of materials and substrates, using bottom-up lithography methodologies and specifically engineered peptides. Further investigations are required to analyse the structural conformation and orientation of the peptides at the inorganic interfaces, and optimize their sequence to increase the selectivity and effectiveness of the deposition and patterning process.

The researchers presented their results in the journal Nanotechnology.

About the author

The work was conducted by a research team from the Materials Engineering Department at the Ben Gurion University of the Negev in Beer Sheva, Israel. The group, which is led by Dr Nurit Ashkenasy, focuses on the engineering and fabrication of electronic devices from biological building blocks. Ravit Nochomovitz, a former MSc student in the group, has developed the micro-contact printing processes of the gold colloids. Maayan Matmor, a PhD student, has worked on the optimization of the polymeric moulds used in the patterning process. Moran Amit, an MSc student, has developed the dispersion and patterning methodologies of the CNTs.